Categorii: Tot - nomenclature - hydration - solubility

realizată de Amira Omotayo 2 ani în urmă

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Chemical processes and properties are essential for understanding reactions and compounds. Stoichiometry helps in determining the precise amounts of substances needed for reactions.

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Extremely Low Concertation: instead of using scientific notation, diluted concentrations are represented in parts per million (ppm), parts per billion (ppb), or parts per trillion (ppt).

Nomenclature is a set of rules for naming chemical substances in a methodical way

Acid (H__)

Polyatomic (__ate)

Binary (__ide)

*strength and concentration of acids/bases are NOT related!

Strong bases: base that dissociates completely into ions in water

Concentration stoichiometry: chemists determine the correct amount of substances needed using stoichiometry

Mole Ratio: a ratio between the coefficients in an equation

Conversion Factor: use the mole ratio as a conversion factor to find an unknown value

Solubility Table: help determine solubility

Water Cycle: the flow of water on, above, and below the surface of Earth

Aquifer: a layer of underground rock that holds a considerable quantity of water; an important source of fresh water

Potable Water: water that is suitable for drinking

Transpiration: the evaporation of water from the leaves of a plant

Water Molecule

% Concertation: in each 100 units of solution, the amount of solute dissolved is measured.

Surfactant: a compound with a non-polar "tail" and a polar "head" that can reduce the surface tension of a solvent.

Solute: the substance that is dissolves in the solvent

Serial Dilution: the stepwise dilution of a substance in solution

Solubility: the amount of solute that dissolves in a given quantity of solvent at a given temperature.

UNSATURATED SOLUTION: a solution that CAN hold more solute in a given amount of solvent at a particular temperature

Dilution Calculations: rearrange as needed to solve for one unknown value

Solvent: the substance that dissolves the solute

Dilution: the process of decreasing the concentration of a solution by adding more solvent

Standard Solution : A solution where the precise concentration is known

Titration Labware:

Burette: a calibrated tube used to dispense very precise and accurate volumes of standard solution ( read from the meniscus)

Funnel: the standard solution is transferred into the narrow burette opening by pouring it through the funnel

Erlenmeyer flask: the solution of unknown concentration is placed in this

Pipette: used to transfer precise and accurate volumes of the solution of unknown concentration to the Erlenmeyer flask

Volumetric Flask: used to prepare the standard solution

Endpoint: the point during a titration when the indicator changes colour

Equivalence point: the point in a titration where the mole ratio of the known solution is stoichiometrically equal to the original number of moles of the unknown solution

Analyte: the other solution in the flask

Titrant: the solution in the burette during a titration (concentration is known)

Titration: is a laboratory process for determining the concentration of a solution by reacting it with a known concentration solution.

pH = “power of hydrogen", it is used to communicate the acidity of a solution, and the amount of hydronium ions

Calculating pH

Changes in “powers of 10” are represented by a Logarithmic Scale

Weak bases: base that dissociates very slightly in water

Weak Acid: acid that ionizes very slightly in water

Strong Acid: acid that ionizes completely into ions in water, meaning that it will conduct electricity well.

Strength: is how completely a compound dissociates in water

Stoichiometry can be used the do the math of acid and base stoichiometry

*Meniscus is were you read the burette properly in a titration lab

Conjugate BASE = the acid AFTER the proton is removed

Hydration: the process where ions are surrounded by water molecules

Dissociation: the process where ions separate from the crystal lattice to dissolve in water

Conjugate acid-base pair = two molecules that transfer protons

Stock Solution : A concentrated solution that needs to be diluted to a lower concentration

Concentration: amount of solute in a solvent

Solubility Curve: shows the solubility of a substance over a range of temperatures

The solubility of ionic compounds generally increases as the temperature rises.

Anion: Non-metals gain electrons

Cation: metals lose electrons

Polyatomic Ions

BRONSTED-LOWRY THEORY OF BASE: a substance that takes (accepts) a proton and any negative ion, such as CN-, OH-, H2PO4

BRONSTED-LOWRY THEORY OF ACIDS: a substance that has a proton (H+) to donate, such as HCl, HNO3 , H2O

THE ARRHENIUS THEORY OF ACIDS AND BASES: Ions can move freely in the solution and thus conduct electricity

Not all bases contain OH

H+ ions cannot exist in solution, and instead they will bond with H2O molecules to form hydronium ion

Activity Series: is a list of metals and their reactivity

The Halogen Activity Series: negative ion (non-metal) is displaced

Acid: releases H+ when dissolved (pro)

Base: releases OH- (when dissolved) (pro)

Neutralization Reactions: A special kind of DD reaction that makes a solution with a pH closer to 7 than either of the reactants

Supersaturated solution: a solution that contains MORE than the maximum quantity of solute (at a given temperature and pressure); dissolving is forced) (unstable)

SATURATED SOLUTION: a solution that CANNOT hold any more solute in a given amount of solvent at a particular temperature

CONCENTRATED SOLUTION: a solution with a relatively large quantity of solute compared to the volume of the solution

DILUTE SOLUTION: a solution with a relatively small quantity of solute compared to the volume of the solution

Conjugate ACID= the base AFTER the proton is accepted/taken

% yield: the goal is the be as close to 100% as possible, to express the efficiency of a reaction

Limiting reactant: the reactant completely used up first, the reaction stops when it runs out

Excess reactant: the reactant(s) left over after the reaction is complete

Stoichiometry: the process of determining the amount of reactants and products in chemical reactions using mathematics

Theoretical Yield: the maximum amount of a product that can form in a chemical reaction (founded through stoichiometry)

Actual Yield: the amount of product that is actually obtained during the experiment

Chemical Change: results in the formation of new substances

Physical Change: while a substance's physical qualities may change, its chemical identity does not

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Entities: different units depending on the substance: atoms, formula units, ions, molecules

The mole (mol): is a counting unit (mass/molar mass)
Mass = number of moles x Molar Mass (m = n x M)

Percentage composition: the percentage, by mass, of each element in a compound; it is found using the formula.

Least common multiple: to find the subscripts between atoms

Amedeo Avogadro

Avogadro’s constant: 6.02 x 10^23 entities (a counting unit) (NA=)

Molar Mass (M): the mass of 1 mol of a substance (found on the periodic table by atomic mass). Use grams/mole (g/mol)

Ions: are simply atoms that have LOST or GAINED electrons

Ionic Compound: is a pure substance composed of positive and negative ions in a fixed ratio.
Hydrate: a compound with a specific number of water molecules chemically bonded to it to form a formula unit

Anhydrate: water can be removed from the hydrate by heating

% mass water =

% Experimental Error

Empirical Formula: shows the simplest whole number ratio of elements in a compound (subscripts are reduced)
Total Ionic Equation: an equation that separates the molecules into their ion forms

Spectator Ions are ions that are not involved in a chemical equation

Net Ionic Equation: a chemical equation that includes only the entities that react during the reaction

The Octet Rule: most atoms want to have 8 electrons in their valence energy level .

Atomic Theory: 1. Atoms are made up of smaller subatomic particles. 2. Atoms, of one element cannot be converted. 3. Atoms of one element share the same properties. 4. Atoms of different element combined to form compounds.

Niels Bohr: Proposed electrons orbit the nucleus in definite energy levels
Bohr-Rutherford Diagram: Shows the number of each type of subatomic particle in their appropriate location

Nucleus: contains protons and neutrons

Electrons: placed in energy levels orbiting the nucleus

Energy Level Diagrams

Electron Configuration: Shows the energy level and subshell (sublevel) with the number of electrons in the subshell indicated as superscript

Orbitals: Different energy levels are divided into energy sublevels

IUPAC system: a Roman numeral in the ion’s name indicates the charge of the ion

Protons

Neutrons is a neutral particle in an atoms nucleus

Isotopes: atoms of one element with different numbers of neutrons

Isotopic Abundance: Different elements have different numbers of isotopes and each isotope exists in different abundances (a percentage %)

Average atomic mass = (abundance isotope 1)(mass of isotope 1) + (abundance isotope 2)(mass of isotope 2)

Radioisoptes: Some isotopes are stable, while others break apart easily

Nuclear Radition:

Gamma ray (γ): high energy electromagnetic radiation

Beta particle (β): negatively charged e-

Alpha particle (α): nucleus of an He-4 atom

Erwin Schrodinger: Proposed the quantum mechanical model based on mathematical calculations
Quantum Mechanical Model (Electron Cloud Model)
Chadwick: particles in the nucleus that do not have a charge (neutrons) and also have the same mass as a proton
Rutherford: Gold Foil Experiment, discovered the nucleus and proved it is positive, surrounded by electrons
J.J. Thomson: Plum pudding” model
John Dalton: Billiard ball model, Atoms can combine and get rearranged to form new substances
Alchemists: tried to transform common metals into gold
Philosophers (400BCE)
Aristotle: proposed matter was made of 4 elements (water, earth, wind, fire)
Democritus: matter could be divided into smaller particles called “atomos”

Chemical Reaction: process where one or more substances change into one or more new substances

Chemical Equations: use chemical formulas
Combustion: A chemical reaction in which a fuel burns in oxygen

Incomplete Combustion: Occurs when the oxygen supply is LIMITED

Complete Combustion: Occurs when there is PLENTY of oxygen, products are always CO2, H2O

Double Displacement: reaction in which elements in two compounds displace each other producing two new compounds

Precipitate: a substance separated from a solution

Solution: homogenous mixture of two or more substances

Law of Conservation of Mass: matter is neither created nor destroyed during a chemical reaction
Catalyst: A substance that makes a chemical reaction occur faster
Single Displacement: a reaction in which an element displaces another element in a compound, producing a new compound AND a new element
Decomposition: A large or more complex compound breaks down into two (or more) simpler products
Synthesis: two reactants combine to form a larger or more complex product

Periodic Trends

Electron Affinity (EA): is the amount of energy required to ADD an electron to a neutral atom in its gaseous state
Electronegativity: is a measure of an atom’s ability to attract electrons in a chemical bond
Bond polarity: to the distribution of e- across a single bond
Non-Polar Covalent Bond (ΔEN ≈ 0): Electrons are shared equally
Polar Covalent Bond (ΔEN <1.7): Electrons are NOT shared equally
Ionic Bond (ΔEN ≥ 1.7): Electrons are transferred from one atom to another
Ionization energy (IE): is the amount of energy required to REMOVE an electron from an atom or ion in its gaseous state
Ionic Radius: an ION’s size, measured in terms of an ion’sradius (in pm)
Atomic Radius: an ATOM’s size is measured in terms of its radius

Lewis symbols (Lewis dot diagram): are used to display the electrons found in an atom’s outermost shell ONLY

Moleclue: two or more atoms connected by chemical bonds

Chemical compounds: a substance formed from two or more elements chemically united in fixed proportions
Oxides: An oxide is a compound of any element combined with oxygen

Acid oxide is an oxide that makes an acidic solution when dissolved in water.

Basic oxides is an oxide which when dissolves with water gives off a basic solution.

Intermolecular forces: Attractive and repulsive forces between molecules/atoms
Dipole-Dipole (polar molecules): attraction between oppositely charged ends

Hydrogen Bonds (dipole-dipole force containing H): a type of dipole-dipole force, that is very strong

London Dispersion Forces (polar and non-polar): happens between all molecules
Intramolecular forces: tractive and repulsive forces within a molecule, compound, or polyatomic ion
VSEPR Theory: model used to predict 3-D molecular geometry based on the number of valence shell electron bond pairs
Lewis structures: drawn on paper in 2D, BUT in reality, these molecules are actually 3D entities
Molecular compound:
Ionization: new ions forming from a neutral compound
IMMISCIBLE: liquids that do NOT mix
MISCIBLE: liquids that mix in ALL proportions
Molecular Formula: shows the exact number of each type of atom in the compound (subscripts are NOT reduced)

Mass multiplier: tells you the exact composition of a compound

Non-Polar Molecule: Equally/evenly distributed e-
Polar Molecule: Unequal distribution of e-
Molecular polarity: refers to the distribution of e- around the entire molecule